.login_page {
  width: 100%;
  height: 100%;
  display: flex;
  justify-content: center;

  background-image: url(../../../public/img/login_bg.png);
   /* 使背景图铺满 */  
   background-size: cover;  

   /* 保持背景图居中 */  
   background-position: center;  

   /* 固定背景不随滚动条移动 */  
   background-attachment: fixed;  
}